W204 Mercedes-Benz C-Class BlueEFFICIENCY

The new W204 Mercedes-Benz C-Class will gain a new specialised range of vehicles known as the BlueEFFICIENCY family. incorporating smart measures and technologies to reduce fuel consumption by up to 12%, while retaining the comfort and safety associated with a Mercedes-Benz.
The two baseline models are the Mercedes-Benz C180 Kompressor BlueEFFICIENCY and the Mercedes-Benz C200 CDI BlueEFFICIENCY, using 6.5 litres and 5.1 litres of petrol per 100 km respectively. CO2 output is 156 and 135 g/km for the two models. A V6 is also available – the C350 CGI but realistically no one who wants to save fuel would opt for a 3.5 litre V6, with BlueEFFICIENCY features or not. The V6 model does 8.4 litres per 100km, a 10% improvement over the normal C350 CGI.

First up is weight reduction – the BlueEFFICIENCY C-Class is between 19 to 32kg lighter than the standard W204. The missing weight can be attributed to things like specially developed windscreens which weigh 1.2kg less, a Maybach-gained technology which allows the windscreen to be made thinner without compromising noise comfort. The firewall’s noise-insulating layer has also been weight optimised, with thickness across the lining varied according to noise input, reducing its weight by about 20%.

The wheels are lightweight wheels – about 1.8kg lighter per piece for a total of 7kg of weight shed that way. They also have an aerodynamic design to help cut fuel consumption. These wheels are wrapped with special Michelin tyres with low rolling resistance, lower by 17% to be exact. The tyres are lighter by 1.7kg per set of tyres.

The body of the BlueEFFICIENCY W204 has a drag coefficiency of 0.25 cD instead of the normal 0.27 cD. This improvement is thanks to smooth underbody cladding, a partially blanked off radiator grille, sealing of joins between the bonnet, bumper and headlamps, wind-tunnel streamlined side mirrors, and a 15mm lower height.

Energy management is also used to cut some fuel usage. For example, the servo pump to the power steering is cut off when the C-Class is being driven in a straight direction, because if you aren’t steering the car you don’t really need steering assistance. This cuts fuel consumption by 0.14 litres per 100km. On the interior, the instrument cluster displays gearshift recommendations and a real time fuel consumption meter.

The C180K BlueEFFICIENCY and the C200 CDI BlueEFFICIENCY have longer final drive ratios – 2.87:1 rather than 3.07:1 for the C180K BlueEFFICIENCY and 2.47:1 rather than 2.65:1 for the C200 CDI BlueEFFICIENCY. These models come with a 6-speed manual, with the 6th gear being an overdrive with a ratio of 0.838:1 for the petrol model and 0.828:1 for the turbodiesel.

Under the hood, the C180K BlueEFFICIENCY has a downsized engine. The 1.8 litre M271 Kompressor is now a 1.6 litre unit, but produces the same output of 156 horsepower at 5,200rpm and 230Nm of torque between 3,000rpm to 4,500rpm. 0 to 100km/h takes 9.5 seconds and it goes on to a top speed of 230km/h.

The C-Class BlueEFFICIENCY cars will be available from Spring 2008 onwards.

After dabbling for years in the IT industry, Paul Tan initially began this site as a general blog covering various topics of personal interest. With an increasing number of readers paying rapt attention to the motoring stories, one thing led to another and the rest, as they say, is history. An avid electronic gadget aficionado as well as big-time coffee lover, he's also the executive producer of the Driven motoring TV programme.